1. Field of the Invention
The invention relates to a rubber vulcanizer and a rubber vulcanizing method. The invention is applicable to manufacturing of any products made of rubber that is vulcanized in dies. The invention is suitably applicable to manufacturing of, for example, an annular or strip-shaped rubber product used for a damper pulley that is fitted on a crankshaft to turn a belt for driving an engine auxiliary machine.
2. Description of the Related Art
Japanese Utility Model Application Publication No. 63-88416 describes an example of a conventional rubber vulcanizer (FIG. 1). The vulcanizer includes an upper die and a lower die. Each of the upper die and the lower die has two recesses. The recesses of the upper die and the recesses of the lower die define rubber molding cavities in cooperation with each other. Because two cavities are defined between the upper die and the lower die of the vulcanizer, two rubber products are vulcanized at the same time.
According to the conventional rubber vulcanizing method, only two rubber products are molded during one vulcanization, and thus the productivity is low.
FIG. 7 illustrates a vulcanizer as a reference example, which is able to enhance the productivity. Note that, the vulcanizer as the reference example is disclosed by the inventors of the invention in order to facilitate the explanation of the invention, and is not known before the filing of the present application, that is, is not prior art, and thus it cannot be used to deny the patentability of the invention.
As illustrated in FIG. 7, the vulcanizer has an upper die 100 and a lower die 101. The upper die 100 and the lower die 101 have a plurality of recesses 103 and a plurality of recesses 104, respectively. The recesses 103 of the upper die 100 and the recesses 104 of the lower die 101 define a plurality of cavities 120 for forming rubber products in cooperation with each other.
As illustrated in FIG. 7, the cavities 120 are present on a plane orthogonal to a pressing direction indicated by an arrow B. The cavities 120 are located at intervals on a straight line. Because the vulcanizer has the multiple cavities 120, the number of rubber products manufactured per unit time is increased. Thus, the vulcanizer has an advantage that the productivity is high.
However, the vulcanizer, which is the reference example, has the multiple cavities 120 arranged in a direction orthogonal to the pressing direction. As a result, a large-sized pressing machine and the large-sized dies 100, 101 are indispensable. Thus, a great initial investment is required. Therefore, if production of the rubber products is discontinued, excessive losses are caused.
Further, with the vulcanizer, it is not easy to flexibly cope with variations in the number of rubber products to be manufactured, so that it is difficult to recoup an initial investment if the number of products to be manufactured varies. Thus, it is not easy to suppress manufacturing costs and to enhance the productivity.